Thanks.
This should be a sticky...

 

I admire your follow thru and well done writing. Should last even longer than a dealer shop job.
One question I have is, was it necessary to press off the axle shafts from the hub or hammer them out?

Great Work.

 

Press Shafts out of Hubs ->



Sorry everyone, I haven't been on for a while; so I'll try to answer everyone's questions.

Some times the splines of the outboard cv joints get seized in the splines of the wheel hub (common to a lot of vehicles, not just MB). If they do get seized, it is extremely difficult to remove them. If this is the case, you do have to press or hammer them out.

Cheers.

 

I'm not usually one to second-guess MB requirements on fluids... but....

Are you saying it (based on what you saw in your diff) that someone in a cold climate (like me in Canada) should be adding about 600ml of fluid, to bring up the 0.9l level to 1.5l?

I'd like to avoid having to rebuild the diff someday down the road if possible... do you think I should add 600ml and it won't cause any adverse effects?

If for absolute certain you know that there is either a)an overflow hole of some kind, so even if the fluid were to 'foam up' or do something weird, it wouldnt cause a problem, or b)extra space that is unused.. thinking of like a gas tank that is 1/2 full... overfilling is a problem but 3/4 full won't cause any kind of problem at all.

If that's the case, I might just top off the fluid by 600ml to 'pre-avoid' the problem

 

Overfilling the diff.



You're absolutely correct about not second guessing manufacturers' fluid requirements. However, like any other manufacturer, MB most likely prescribes the minimum lubrication requirements. If there is a better fluid on the market, by all means use it. I used Royal Purple 75W90 full synthetic in my own diff which I rebuilt over 7 months ago - Still Good.

As for overfilling the diff - not generally a great idea. Having said that however, the only problem you may be faced with is slight leakage from the axle seals. If you grossly overfill it, the fluid will leak out from the top vent when it expands from heat generated by the hypoid gear friction.

So - A little bit (like 600ml) should be ok. Like I said, I did my own this way and it's been good for the last 7 months.

Cheers.

 

What were the symptoms that the rebuild was needed? On my 06 ML500, I dont know if I need new tires or there some thing else (like hub bearings). It sounds like I'm running on grooved pavement when I'm driving. The sounds seems to lesson as I gain speed. Any ideas? It has 65k miles.

 

Symptoms of Bad Diff Bearings.



There are a lot of different noises that can come from the driveline of any vehicle. There are literally dozens of different bearings, gears, clutches etc.

Most common driveline noises are are from tires, wheel bearings, transfer cases and differentials.

On the ML, as I mentioned in my first post, in my opinion the carrier bearings are not stron enough to withstand the lateral forces placed on them by the hypoid transmission of power. If you look at the prefix on the bearing part number it says "LM". Now if you open any Timken catalogue, you will find that "LM" or "KLM" stands for light - to - medium duty.

So to answer your question, the noise that warranted the rebuild was a humming/growling noise coming from the front of the vehicle that increased with road speed and did not change under load.

Hope this helps.
Cheers.

 

What kind of oil is recommended for the front and rear diff in the 164?

 

I read that you can use Mobil 75w90 LS gear lubricant.

What fluid did you use to refill the diff?

 

Bearing Preload

I read that you can use Mobil 75w90 LS gear lubricant.

Im not sure however of its accuracy. If i cant find an equivalent fluid, I will have to buy the Mercedes fluid from the dealer at $48 a pop.
I bought it before to drain and check the diff fluid. Sure enough mine had alot of metal shavings and the dreaded growling noise. This however if for my 2006 ML350. not sure if the diffs are the same.

I replaced the drivers side front wheel bearing only to find out it is the differential.
I am going to do this job myself and I too, will post as many pics and details I can.

What I don't understand fully is checking the preload and removing and stretching the crush collar.
I will do more research on this while the bearings are being shipped in.

What fluid did you use to refill the diff?

Hey Theoneuafter.

I think I somehow missed your questions, so I'll try to get them answered for you.

Fluid:

Most diffs (for abt 100 years now) have used really heavy weight oil (80W90, 90W140, etc) - MB is no different. I think original Benz fluid is 75W90 Full Synthetic and obviously with hypoid friction additives/friction modifiers. I used Royal Purple Full Synt. 75W90 in mine. You can actually buy hypoid additive for "extra protection" and add some to the oil before or after you fill the diff with whatever oil you are going to use. So basically any good (preferably synthetic) 75W90 oil for differentials (with hypoid additive) should be fine. How do you tell if the oil has hypoid friction modifiers? Well, open the bottle and smell it - it has a very distinct/nasty smell to it. If you compare it to regular 10w30 (for example), you'll know right away what I'm talking about.

Bearing Preload:

Bearing preload is nothing more than an fancy term used to describe how much pressure is put on the bearing to press the bearing cone into the bearing cup. This force/pressure has to be just right - too tight and the bearing will overheat and fail, too loose - the bearing rollers will bounce against the cup (also called race) and fail due to mechanical damage.

Crush collar:

The crush collar has also been used in diffs for decades if not over a century. What it is there for is to provide something for the bearing cones to but up against when you tighten the pinion nut. It is called a "crush bearing" or "crush collar" because it actually gets crushed by the force you apply to the pinion nut ( you are literally tightening the nut against the sleeve/cush collar). To properly check preload (or to make sure that the bearing cones are not too tight or too lose against the cups) you need to get an inch/pound analogue torque wrench and turn the pinion nut with it after you tightened the pinion nut. If it takes too much torque to turn the pinion, this means that the bearing cones are too tight against the cups. The only way to correct this is to stretch or replace the crush collar and tighten the pinion nut again against the crush collar while crushing it to such a distance that the bearings end up being pressed into the races just right. If they're too loose, then it's easy to correct - just tighten the pinion nut some more until you get it right.

Whe you're doing your pinion preload and fine tuning the pinion nut torque (obviously after you've tightened it initially) do it in small steps - like 1/32 of a turn and re-check. Do this until you get it just right.

I've found a couple of cool videos that you can check out to get a visual representation of what I'm describing:

- this one is tricky because it shows preload on the pinion and the carrier bearings. So abt 15-20 inch/lbs for the pinion bearings alone and 20-25 inch/lbs with the carrier bearings (basically all four bearings pre-loaded should take about 23 inch/lbs pinion torque to turn)

This one is actually perfect, by far my favourite:

- Do it exactly how this guys shows it you you'll be off to the races, just remeber - no more than 18-20 inch/lbs if the carrier is not installed. Hope this helps.

 

Transfer Case Rebuild Kits Available

Hi Everyone.

Well, since I rebuilt my diff, the transfer case went on me. Much the same noise and the differential. Took it apart and found one of the bearings inside the trasfer case failed.

I rebuilt it myself and since then put together a complete kit of all bearings, seals, and a new chain.

If anyone is interested, let me know. I'll be glad to help with instructions, etc. It was actually easier to do the transfer case than it was the diff.

Cheers.

 

Hi Everyone.

Well, since I rebuilt my diff, the transfer case went on me. Much the same noise and the differential. Took it apart and found one of the bearings inside the trasfer case failed.

I rebuilt it myself and since then put together a complete kit of all bearings, seals, and a new chain.

If anyone is interested, let me know. I'll be glad to help with instructions, etc. It was actually easier to do the transfer case than it was the diff.

Cheers.

Are you running you ML off road or do you have high mileage?? Trying to figure out why you have so many drivetrain failures.

 

Nice. That explains it perfectly!
You have a PM.

 

Did you reuse the collar?

 

I reused the old crush collar. I did have to stretch it a bit to make it work.

 

How do you "stretch" a crush collar?

I've read your "procedure" on the front page and since I am in the process of doing this myself currently, I dont believe you actually did one of these yourself. I beleive you just put together some seemingly correct steps from looking at pictures of one in order to sell your bearing kits on eBay. As I have actually torn mine down and am rebuilding it now, I can verify that you have several steps that are out of order and would be quite clear that they are out of order to anybody who has actually done this.

 

Awesome work!

 

W164 Repeat Offender?

Hey NewMLGuy!

Thanks so much for all the postings you've put up about the W164 differential issues. I wanted to reach out to you because I recently purchased a 2009 ML350 with 96000. Runs great and is in great condition. My concern is recently I've been hearing moan from the front (mainly at low speeds) and a light vibration while driving. This is my second W164, so I am familiar with the differential failure (my 2006 fell victim to it). Can you offer any suggestions? I want to try and attack the issue before it grows. Thanks again!

 

Hey NewMLGuy!

Thanks so much for all the postings you've put up about the W164 differential issues. I wanted to reach out to you because I recently purchased a 2009 ML350 with 96000. Runs great and is in great condition. My concern is recently I've been hearing moan from the front (mainly at low speeds) and a light vibration while driving. This is my second W164, so I am familiar with the differential failure (my 2006 fell victim to it). Can you offer any suggestions? I want to try and attack the issue before it grows. Thanks again!

Hi.

Vibrations (especially at highway speeds) are typically caused by misbalanced tires, and rarely drive train issues. If you are getting a fine vibration at low speed you should have it checked out (definitely not tires and may be difficult/expensive to diagnose).

Driveline noises are best diagnosed with a stethoscope by listening to different parts of the drive train while it is operating. The '09s use the same diff as the '06 (if I'm not mistaken), so it would be a great idea to have it checked.

I would take it to a mechanic you trust, have him put the truck on the hoist and run it in drive while it's up in the air and go over all the main parts of the drive train with a stethoscope. He should be able to pinpoint your noise if it is coming from the drive train. Keep in mind that the traction control system will not let you do this any faster than a coupe of MPH which may make it difficult to get a conclusive diag if the problem is not bad enough to be audible.

Change the diff oil and look for metal shavings/debris in the oil, etc.

Hope this helps. Cheers.

 

Wheel Bearing or Diff??

Thanks for all the great info NewMLGuy, I'm sure we all appreciate the input and assistance you have provided here.

My question is what is the best way to diagnois if I might have front diff troubles or just a wheel bearing...

I have a '06 ML500 w/87,000mls, the noise we're hearing is a low "shaa-shaa-shaa" type of noise, seemingly from more the drivers side than the passenger side.. But definately from the front wheel / axle / diff area... It isn't heard at very at low speed but definately above 10-15mph and obviously increases in frequnce with speed. It gets loudest at about 35-55mph but above 65-70mph is less loud.

Is my best indicator of diff bearing damage to change the oil and inspect for metal particles?

Thanks for any input or advice - Nick

 

Thanks for all the great info NewMLGuy, I'm sure we all appreciate the input and assistance you have provided here.

My question is what is the best way to diagnois if I might have front diff troubles or just a wheel bearing...

I have a '06 ML500 w/87,000mls, the noise we're hearing is a low "shaa-shaa-shaa" type of noise, seemingly from more the drivers side than the passenger side.. But definately from the front wheel / axle / diff area... It isn't heard at very at low speed but definately above 10-15mph and obviously increases in frequnce with speed. It gets loudest at about 35-55mph but above 65-70mph is less loud.

Is my best indicator of diff bearing damage to change the oil and inspect for metal particles?

Thanks for any input or advice - Nick

Nick,

Stethoscope is the only sure way to diagnose driveline noises. Sha-Sha-Sha does not sound like diff bearings.

Wheel bearings typically get louder during turns - try a freeway on-ramp if the noise goes away or gets worse, then it's a wheel bearing. Now you'll just have to figure out which side.

Diff carrier bearings get louder with speed. Period. They make a constant growling noise which increases in pitch/loudness with speed only. Varying load, gear, direction, etc do not affect it.

Shavings in the oil are never good, but don't panic right away if you see fine metal dust particles - this may be normal wear and tear.

Good luck.

 

We just had our front diff replaced for free by our dealer. We were 4000 miles over warranty. MB goodwilled the total cost.
We are so thankful they fixed it. The cost for them to replace it was ridiculous.

 

You should post the dealer's Name and Address - give them a little pat on the back. Not too many good ones left around any more.

Congrats!

 

Any pics of this process?

 

Bearing quality?

Since I sold my W164, I have not looked at this forum for some time, bhut reading through some of the good comments and some not so good ones, I have to join in.

I have been an engineer in the bearing industry since 1971, although now retired. My specialty was failure analysis, applications and quality control.

I know that some of the major companies including but not limited to Timken, seem to indoctrinate some of their younger staff into believing they are the only "good" manufacturer in the world. So you have to be careful of some of the comments made.

One of the Ebay ads showed some NTN brand bearings. No these are not Timken. But they are one of the four top Japanese brands, and equal to the best bearings made in the world. Anyone who tries to deny that is showing ignorance. I would be happy to use them in any vehicle of mine.

Both the pinion bearings come with the prefix "HM" whilst the side carrier bearings come with "KLM".

The "HM" prefix (Heavy-Medium) indicates a bearing of thick proportions, where the outside is much larger diameter than the bore, or shaft size. This allows for a steep taper angle, hence a high thrust capacity, as required for the pinion.

The "LM" prefix (Light-Medium) indicates a bearing of thin proportions, which has a finer taper angle more suitable to a higher radial load. These proportions allow for the use of smaller diameter rollers, so many more rollers can be fitted, giving the bearing a very high capacity.

So the LM sizes may have a higher capacity than the HM sizes!

The "K" prefix is used by SKF and *** to denote a bearing made to Timken specification, i.e: an imperial sized bearing. All other SKF/*** tapered roller bearings are ISO metric sized, usually 5 numerals starting with "3".
All other European manufacturers have copied this system.

Timken, have never used this "K" prefix in any of their own factories, especially in the USA. However as an expansion program, they have bought out several factories to expand ther range. These include Torrington-Fafnir (USA) encompassing IRB in Spain. They also bought out a factory in Poland.
Both the IRB and Polish bearings use the "K" prefix. And they now come in the traditional orange and black packets.

We have noticed a higher than normal failure rate with bearings from these plants, but I would expect Timken have put a lot of effort into improving the product. Note: I would not be prepared to say these Polish bearings are the cause of the Mercedes diff problem.

It is strange that the KLM503349/503311 box is marked "IsoClass" as these are NOT ISO BEARINGS. But it may be that they used a convenient box when it was time for packageing.

Timken USA does not make size LM503311. It is a minor but essential variation of the LM503310. Only Timken Poland claims to make this size.

Other pictures show the bearing etching with "USA" and the "KLM" prefix. These marks do not appear in the one picture, and they should not appear on the same bearing. If they are on the same bearing, then I would expect they are a Chinese or similar forgery.

Now in summation:-
The poor service life that seems to appear in Mercedes front diffs, is probably totally unrelated to the selection of the bearings. To determine the cause of failure I would need to inspect the failed bearings, and possibly the complete diff.
It could be that they use the same gear set for front and rear which reverses the load as the front diff points the opposite way to rear. This has been normal practise until recently with other makers, but rarely shows a problem when they use part-time 4WD.

The extremely short service life referred to in one post is possibly due to another reason, - likely preload or fitting damage.

One last thought to end this text book.
It is suggested that you can re-use the seal. For its low replacement cost this is unwise as future failure is probable.
And over filling the diff with oil is also a no-no! It would cause frothing of the oil leading to overheating, poor lubrication and posible seal leaks.

 

Very Insightful

[...Since I sold my W164, I have not looked at this forum for some time, bhut reading through some of the good comments and some not so good ones, I have to join in.

I have been an engineer in the bearing industry since 1971, although now retired. My specialty was failure analysis, applications and quality control. ...]

Ian,

Very insightful write-up. Thank you for sharing.

The original bearings used by Magna Powertrain (the company who make these diffs for MB) are stamped "KLM503311 POLAND SD" (see attached picture). So what you say about the different factories makes sense. One could even speculate further and say that it probably makes sense, if Magna's power train products are built or assembled in or near Poland. Have a read here: Magna chooses Poland over Hungary, Austria for car assembly project | neurope.eu

Here's another pretty cool read, although only vaguely related: Magna Powertrain - Wikipedia, the free encyclopedia

These 503311 are obviously a highly guarded secret and must be made by Timken specifically for Magna as an OEM only part. I run into this sort of thing at work all the time: big manufacturers will build parts for their larger clients according to "custom" specifications only changing one or two things ever so slightly from one of their commonly available products, and nobody but them can buy these OE parts. These sort of practices are unfair and highly illegal (in US and Canada at least, as part of Antitrust and Competition laws) but are, unfortunately, quite commonplace.

This is also the case with the bearings Magna used in the Transfer Cases on these trucks. Only the situation with the T/C bearings is worse - they are stamped with a very common number, but if you look at them they are completely different from what that number bearing is supposed to look like. I think the sad part about all this is that they do this on purpose.

Could it be that since the Polish made bearings were having so many issues, Timken started making them in the US under KLM or LM prefix? I'm sure that if they did though, they would never make this sort of information public. We're supposed to pay MB almost $10,000 for a new transfer case or diff as opposed to replacing a couple of $20 bearings, which should never have failed so soon anyway, remember!? Christ, I have a 35-yr old Chevy with the original diff in it and it is just fine.

As for the ISO class - it must have been a packaging issue. I just looked at the current stock I have here and there's no mention of ISO on the box. And as for the rest of your comments - I completely agree with them as well - well put!

Thanks again.

 

Yes that pictured bearing cup is consistent with genuine production from Poland.

It differs from the standard only in a minor way that may safe an extra machining process in the diff. Typically a radius variation, or controlled width setting.

Usually Timken USA tend to make propriety parts to supply unique OE applications and give them a number like NP123456 which is just refferring to a drawing number. This item is them only sold to the OE customer.

imilarly, the Japanese may make a unique OE part, but they use standard numbers and they agree not to sell it to the aftermarket for 7 years.

These are just commercial ways of avoiding the pointless efforts of getting patents.

 

hello guys,

sorry i am new here and my english is not very good. i have ml500 w164 and my transfer case has once failed already, after replacing it the same problems are starting to this one as well, can you please tell the bearing sizes and part numbers to replace it.

thank you, i appreciate it.

 

Transfer Case Bearing Numbers



beq,

Unfortunately the bearings inside these transfer cases are specially made for Magna and I don't know who makes them. I get them through a supplier who does not tell me the manufacturer either. Sorry, but I can't help you with the numbers.

I can sell you the bearings because I have them here, but if I tell you the numbers you will not be able to find them. The numbers that are stamped on the bearings do not correspond to the actual bearing itelf - so if you go out and buy the bearings with same part numbers, they will not work in your transfer case.

I can put a set on e-bay but I don't think I can ship to Tbilisi, Georgia. Does DHL deliver there?

Hope this helps.

 

Just ANOTHER part(s) that Mercedes put on the ML that is not strong enough to handle the weight of the vehicle. The other was the steering rack and pump along with trans valve body problems. I've never had a car with front diff failure, many with miles well over 200K. The real issue here is poor components that a large majority if not all of the 2006-2011 ML's. are plagued with. If in year 2006, M-B was mandated to give every ML a 10 year 100000 mile powertrain warranty, the company would have gone near bankrupt.

 

Gentlemen,

To put the issue of ‘fake’ or ‘real’ bearings to bed once and for all and so that nobody has to read any more rants by Mostar1, here’s what I’ve done:

The original link posted to eBay no longer works – the listing has been removed.

I have sourced the original OEM Timken Bearings from Poland. They are the original genuine ones. They are expensive and you can get them here: 2006 12 Mercedes ML W164 Front Diff Bearings Hard TO Find NOT Sold IN USA | eBay

I will be posting another listing for just the pinion bearings soon. As soon as I do, I’ll make a note for everyone on here.

I’ve been being asked a lot for the transfer case bearings, rebuild procedures, pictures, etc., as well. I will be listing a kit on eBay soon. As soon as I do, I’ll let everyone know as well. And of course I’ll try to do a step-by-step write-up on how to DIY.

Thanks for everyone’s support and patience. And a big thanks to Iankayem, the retired bearing failure analysis engineer who chimed in on the issue in this thread, for clearing things up for everyone.

 

MOSTAR IS BACK !!!

Damn it, mostar1 is back!

No, not here, thank god. Dan (AKA mostar1, AKA lasicm) is on MBWorld doing the same stupid things he was doing here before he got banned.

So I decided to open a whole new thread in the W164 part of the forum and dedicate it to Dan's fake bearings from China that he sells on eBay while passing them off as the real thing! Click here.

He has recently gotten away from from his uber-patriotic USA Made Timken stories and now claims that he has sourced French made KLM 503349 bearings (which are so Fake) which he pairs with Polish Made KLM 503311 race (the race actually looks authentic, I'll give him that). This is a NO-NO to begin with - you can never mix and match sets, but what does it matter to him? He only cares about selling the bearings!

From our engineer friend who told us about the origin of these bearings above, we all know that these misterious KLM503349/11 bearings are only made in Poland and are always sold as a set.

Anyhow, I will stop 'beating a dead horse' now and leave you with a new thread.

Cheers,

Thanks for all your input!

 

He has recently gotten away from from his uber-patriotic USA Made Timken stories and now claims that he has sourced French made KLM 503349 bearings (which are so Fake) which he pairs with Polish Made KLM 503311 race (the race actually looks authentic, I'll give him that). This is a NO-NO to begin with - you can never mix and match sets, but what does it matter to him? He only cares about selling the bearings!

Have never seen roller bearings manufactured but am told one of the final steps in manufacturing is the inner race and outer race are ground as an assembly so the inner and outer tapers are identical.

 

I keep forgetting to ask. Could someone sticky this thread? Please.

Thanks.

 

I won't sticky it but I will add it to the DIY thread that's already stickied.

 

Just found another member did that same rebuild (I believe on a 2007 R500). He also posted some nice pics, specs and a write-up. Nice. You should check it out: http://www.benzworld.org/forums/w251-r-class/1588622-06-bad-front-differential-3.html

The diff looks exactly the same as the W164. There's also a bit there about a transfer case, which also looks the same as the w164 with the same blown apart input shaft bearing as my w164 transfer case.

 

Hi,
Since you rebuild your diff. could you tell me waht time of diff. is like LSD Limited slip diff.?
Thank you

 

Regular Differential



Nope. These are a regular, straight-forward differential.

 

ML350 Front Diff Repair

I posted this in another front diff forum, but saw more technical advice here. sorry for the duplication. Please let me know if this is the wrong place for this post/question:

Hi all. I'm Shawn, and I am new to this forum. Here is what I have: 2006 ML350, grinding noise that I swore was drivers side wheel bearing (before I read some threads on this site ). Changed out wheel bearing myself: DID NOT REPLACE HUB AS MANDATED BY DEALER AND WOULD NOT EVER REPLACE PERFECTLY GOOD HUB JUST BECAUSE MBUSA SAYS SO. Noise still there.

Figured that persistent noise was front diff/carrier bearings, but took to MB to make sure: $195.00 diagnositic confirmed differential is failing. This is probably a good investment, as the wheel bearing was $137.00, and probably did not need to be replaced.

Am going to repair the diff my self as well and have a couple of questions....

1. All of the bearing chatter on this site confused me. Which bearings should I buy: I think I can only get them on Ebay, but there are a lot of them there...which ones are the good ones?

2. Should I just replace the carrier bearings or do the pinion bearings as well. The failure seems to be the fault of the carrier, and the only way to inspect the pinion bearing is to remove it. Carrier bearing replacement is much easier, and I don't know that it makes sense to mess with a good pinion set up (removing and replacing) if that is not a problem in these diffs.

3. Do the carrier bearings use any sore of crush sleeve? If so, what is the part number? I know you can stretch and reuse these, but you can also break them, and I would like to have them on hand new in case they are needed.

Thanks in advance!

Also, if this should be posted somewhere besides here, please let me know and I will repost in appropriate location.

 

I posted this in another front diff forum, but saw more technical advice here. sorry for the duplication. Please let me know if this is the wrong place for this post/question:

Hi all. I'm Shawn, and I am new to this forum. Here is what I have: 2006 ML350, grinding noise that I swore was drivers side wheel bearing (before I read some threads on this site ). Changed out wheel bearing myself: DID NOT REPLACE HUB AS MANDATED BY DEALER AND WOULD NOT EVER REPLACE PERFECTLY GOOD HUB JUST BECAUSE MBUSA SAYS SO. Noise still there.

Figured that persistent noise was front diff/carrier bearings, but took to MB to make sure: $195.00 diagnositic confirmed differential is failing. This is probably a good investment, as the wheel bearing was $137.00, and probably did not need to be replaced.

Am going to repair the diff my self as well and have a couple of questions....

1. All of the bearing chatter on this site confused me. Which bearings should I buy: I think I can only get them on Ebay, but there are a lot of them there...which ones are the good ones?

2. Should I just replace the carrier bearings or do the pinion bearings as well. The failure seems to be the fault of the carrier, and the only way to inspect the pinion bearing is to remove it. Carrier bearing replacement is much easier, and I don't know that it makes sense to mess with a good pinion set up (removing and replacing) if that is not a problem in these diffs.

3. Do the carrier bearings use any sore of crush sleeve? If so, what is the part number? I know you can stretch and reuse these, but you can also break them, and I would like to have them on hand new in case they are needed.

Thanks in advance!

Also, if this should be posted somewhere besides here, please let me know and I will repost in appropriate location.

Hi Shawn, welcome to the forum.

Here are the answers you're looking for:

1. Good bearings are the original ones (Genuine Timken). Others may be slightly different size (thickness) so if you use them you may clearance/pre-load issues and you may have to remove/add shims, etc. It's just a pain in the butt that you don't need. Setting up a diff from scratch can make you go grey or pull out the hair you have left and go bald ;-) I sell them here: 2006 12 Mercedes ml W164 Front Differential Bearings Hard to Find not Sold in US | eBay

2. You CAN just replace the carrier bearings and double check all your run-outs, clearances, back lashes and contact pattern and if all is good you should be off to the races...BUT!!! It's not recommended. Any time you take a diff apart and replace parts in it (i.e. carrier bearings) you may change the clearances inside which may require you to play with pinion depth anyway so why not just replace the pinion bearings from word go and set things up the right way from the very beginning. Plus, the pinion bearings have just as many miles on them as the carrier bearings (which have failed), plus many, many other arguments which probably should steer you toward replacing all bearings in the diff if you are going to go through the trouble of taking it out and apart.

3. Carrier bearings do not use anything other than some shims (on these diffs anyway). As long as you put the same shims back in the same place you took them out of and as long as the bearing and cone are the same size (this last one is very important), that's all you should have to do with the carrier. The pinion uses a crush sleeve. Don't know the part number, but you may be able to get one aftermarket if you are able to measure it (mike it one you have it apart and phone a transmission shop supplier with the measurements - they should be able to get one for you). Stretching them is no big deal, just heat it red hot and hammer lightly a couple of times (you only need to peen it or stretch it like 0.060" to 0.090", so don't overdo it and break it).

Hope this helps. If you have any questions, feel free to ask.